Pulley systems are commonly used in exercise equipment to drive resistance loads. One technique which allows a user to vary the resistance of the force against which the user exercises is the incorporation of variable pitch pulleys, or split pulleys, into a slave pulley of the pulley system. This technique requires the position of the belt on the slave pulley to be controlled in a reliable and efficient manner to adjust for low resistance through very high resistance, as desired by the user.
While available belt control systems sometimes utilize variable pitch slave pulleys, problems associated with such systems have not been fully addressed. For example, when removing tension from a pulley belt, the belt can whiplash and jump off a slave or a drive pulley, necessitating reinstallation of the belt onto the pulleys. In some systems, the means of controlling belt tension by application of force to the belt are difficult to operate. In other systems, the means of controlling belt tension are not sufficiently precise to provide accurate changes in resistance to the exercise system.
In another aspect of available exercise systems, upper body exercise machines sometimes utilize the direct drive of an inertial flywheel with resistance adjusted through frictional engagement of a rim brake on the flywheel. Other systems use magnetic brakes, which are cost prohibitive. One limitation of some presently available upper body exercise machines is the utilization of a resistance loading system which does not provide a smooth or accurately adjustable load. Another limitation of some systems is the incorporation of crank arms which are not adjustable for different sized users. Yet another similar limitation is the incorporation of seats which are not easily positioned for the proper utilization of the exercise machine by different users.
It is against this background that the significant improvements and advancements of the present invention have taken place.